M16C26 Datasheet, PDF (168/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

Udenvdeelropment
Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative
A-D Converter
and
subject to change.
SINGLE-CHIP 16-BIT
M16C/26 Group
CMOS MICROCOMPUTER
(a) Sample and Hold
Sample and hold is selected by setting bit 0 of the A-D control register 2 (address 03D416) to "1". When
sample and hold is selected, the rate of conversion of each pin increases. As a result, a 28 fAD cycle is
achieved in 8-bit resolution and 33 fAD in 10-bit resolution. Sample and hold can be selected in all
modes. However, in all modes, be sure to specify whether to use sample and hold before starting A-D
conversion.
(b) Caution of using A-D converter
(1) Set the port direction bits corresponding to the following pins to input: those P10 pins to be used for
analog input, plus external trigger input pin (P15).
(2) In using a key-input interrupt, none of 4 pins (AN4 through AN7) can be used as an A-D conversion port
(if the A-D input voltage goes to ‘‘L’’ level, a key-input interrupt occurs).
(3) Insert the capacitor between AVCC and AVSS, between VREF and AVss, and between the analog input
pin (ANi) and AVSS, to prevent a malfunction or program runaway, and to reduce conversion error,
due to noise. Figure 1.16.9 is an example connection of each pin.
Microcomputer
VCC
AVCC
C4
VREF
C1
C2
VSS
AVSS
C3
ANi
Note 1: C1 ≥ 0.47uF, C2 ≥ 0.47uF, C3 ≥ 100pF, C4 ≥ 0.1uF (reference)
Note 2: Ensure these connections are as thick and short as possible.
Figure 1.16.9. Example connection of VCC, VSS, AVCC, AVSS, VREF and ANi
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